Melt transport rates in heterogeneous mantle beneath mid-ocean ridges

摘要: Abstract Recent insights to melt migration beneath ridges suggest that channelized flow is a consequence of melting heterogeneous mantle, and spreading rate modulates the dynamics localised flow. A corollary this finding both mantle heterogeneity have implications for speed time scale migration. Here, we investigate these using numerical models magma in plates. The predict broad distribution speeds characteristic sub-ridge mantle. Within region, magmatic fastest regions average fusibility; surprisingly, magmas from sources above-average fusibility travel ridge longer time. Spreading has comparatively simple consequences, mainly resulting faster segregation at higher rates. computed scales are short enough preserve deep origin 230 Th disequilibria and, under favourable parameter regimes, also 226 Ra excesses. An important prediction induces significant natural variability into U-series disequilibria, complicating identification relationships between properties or chemical signatures heterogeneity.